Events

Chloramphenicol (CAP) is a broad-spectrum antibiotic, effective against a wide range of microorganisms but has serious toxic effects on humans. The absence of safe residue levels in foods has led many countries to accept the Minimum Required Performance Limit (MRPL) defined by the EU at 0.3 ng/g. The purpose of this study was to experiment a new ion source operating at atmospheric pressure based on Thermo Desorption by Laser Diode (LDTD) for the determination of CAP residues in honey. The LDTD ionization source allows the analysis of CAP by mass spectrometry with minimal sample preparation: a simple liquid-liquid extraction of CAP from an aqueous dilution of honey using ethyl acetate, without further purification. Then 2 µL of the extracts were deposited in a dedicated 96 well holder, ready for the analysis after 1 minute of drying. A laser diode is used in the transmission geometry to produce a rapid thermal desorption of the dried sample. Intact desorbed molecules are carried in a gas flow to an APCI region to undergo negative chemical ionization at atmospheric pressure. Products ions of precursors m/z 321 and 323 were monitored and used for quantification and confirmation. Thiamphenicol and d5-CAP were used as internal standards. CAP was identified and quantified at the MRPL of 0.3 ppb. The data for various honey samples are presented.